Core catcher



Feb. 1 l, 1936.

J. H. HOWARD ET AL CORE CATCHER Original Filed Aug. 7, 1933 Patented Feb. 11, 1936 1 CORE CATCH ER,

John H. Howard, Huntington Park, and Alfred C. Catland, Alhambra, Calif., assignors to Globe Oil Tools Company; Los Nietos, Calif., a corporation of California Original application August '7, 1933, Serial No. 684,018. Divided and this application February 2, 1934, Serial No. 109,461

8 Claims. (01, 255-72) This invention has to do with a well tool and has particular reference to a core catcher for use in a well core drill. A general object of the invention is to provide a practical, eifectivecore catcher of simplified and improved construction. 5

This application is a division of our application as indicated by line 3-3 on Fig. 2 and illustratfor United States Letters Patent entitled Core ing the dogs in the vactuated positions. drill, Serial No. 684,018, flled August 7, 1933. v The core catcher of the present invention may An object of this invention is to provide a novel be employed in core drills varying considerably and particularly eifective core catcher that is in construction. In the following detailed dis- 10 capable of dependably supporting and retaining closure of the invention we will describe a typcores of both hard and soft earth formations, ical preferred form of core catcher operating in and cores that are broken or shattered. a core drill of the type fully described and claimed Another object of the invention is to provide in our co-pe'nding application, mentioned above, I a core catcher of the pivoted dog type that is and our application for United States Letters 5 rotatably mounted in the core drill so that it is Patent entitled Core drill, filed February 2, 1934, free to float, whereby it may be held against ro- Serial No. 709,460. It is to be understood that tation through contact with the core during the the invention is not to be construed as limited or drilling operation. restricted to the specific form or application about Another object of the invention is to provide a to be described, but is to be taken as including 20 core catcher embodying replaceable core engagany features or modifications that'may fall withing dogs pivotally mounted in a simple and dein the scopeof the claims. pendable manner. The core:drill illustrated in the drawing in- Another (Erbject of the invention is to provide eludes an outer barrel I0 provided at its upper a core catcher having core engaging dogs which end with a connecting member or sub It for 26 each have two faces or shoulders spaced apart facilitating connection of the drill and a well and adapted to cooperate with two seats on the drilling string. A sub I8 is provided on the lower body of the core catcher to dependably support end of the outer barrel l0 and carries a bit head the dogs when they are holding the core. sub IS. A bit head H is screw threaded on the A furthenobject of the'invention is to provide sub l9 and is provided with circumferentially 30 a floating or rotatably supported core catcher spacedcutting blades 2| for making an annular embodying pivoted core gripping and supporting cut in the earth formation. The bit head H is dogs mounted and arranged so that the outward tubular and has an internal annular recess 25. thrusts towhich they are subjected while acting An inner barrel I2 is provided in the drill for reon and supporting the core, are transmitted di-" ceiving the core cut'by the bit head II. The inrectly to the bit head or other surrounding part ner barrel I2 has a ring or' enlargement 29 on its of the core drill. lower end which is .rotatably supported in the A further object of the invention is to provide recess 25 of the bit head II. "The lower end pora core catcher including a sectional body, pivoted tion of the enlargement 29 has an internal ancore engaging dogs and a simple eflective means nular recess 33 which, together with the recess 25 40 for connecting the sections of the body that is of the .bit head ll, carries or contains the core such that the core catcher may be easily and catcher. The lower end of the inner barrel I2 is quickly taken apart for repair or for the, replaceopen for the reception of the core while a valve ment of its parts. It is provided on the upper end of the inner bar- Other objects and features of the invention rel to prevent the downwardly flowing circulation will be better and more fully understood from the. fluid from entering it. The valve I4 is adapted following detailed description of a typical form to open to permit the discharge of fluid from the and application of the invention,. throughout inner barrel I; as it is displaced by the entering which description reference may be had to the core. The inner barrel I2 is spaced from the inaccompanying drawing, in which: .7 terior of the outer barrel l0, providing an an- Fig.1 is aside elevation of a core drill carrynular fluid passage S which communicates at its ing or embodying the core catcher of the present lower end with ports in the enlargement 29. invention with the principal parts of the drill The ports 60 communicate with discharge pasand core catcher broken away to appear in longisages 62 in the bit head ll through an annular tudinal cross section. Fig. 2 is a top or plan view 65 -of the core catcher apart from the drill, with a portion broken away to appear in horizontal cross section, being a view taken substantially as indicated by line 2-2 on Fig. 3. Fig. 3 is a vertical detailed sectional view of the core catcher taken recess provided in the interior of the bit head.

. shoulders 5|.

The core catcher provided by the invention includes, generally, a sectional body A rotatably supported in the core drill, pivoted core engaging dogs B on the body A, and means C for operating the dogs B.

The core catcher body A is adapted to be rotatably arranged in the core passing or receiving opening of the core drill in a position where its dogs B may have the desired engagement with the the core. In the particular core drill illustrated in the drawing the body A is rotatably supported in the lower portion of the bit head recess 25 and extends upwardly into the recess 33 in theinner barrel enlargement 29. The body A is tubular or annular and has limited longitudinal movement in the core drill. The lower wall of the recess 25 limits the downward movement of the body A while the upper wall of the recess 33 limits the upward movement of the body A. In accordance with the invention the body A is sectional comprising two sections or rings 35 and 36. The rings 35 and 36 are telescoped one within the other, the ring 35 being the outer ring and surrounding the major portion of the ring 36. The body sections or rings 35 and 36 have opposing contacting faces 31. The faces 31 are preferably inclined with respect to the longitudinal axis of the body. The upper ends of the rings 35 and 36 may be flush to provide the body A with a fiat upper end. The inner ring 36 may project downwardly beyond the lower end of the outer ring 35, providing the body A with a reduced lower end portion to seat or operate in the portion of the bit head recess 25 below an inclined upwardly facing shoulder 21 on the wall of the recess 25. The opening 38 in the body A is in vertical register and alignment with the core receiving opening 34 of the bit head ll. 1

In accordance with the invention an annular space or groove 43 is provided between the contacting bearing faces 31 of the rings 35 and 36. In the particular structure illustrated in the drawing the space or'groove 43 is formed in the inner ring 36 and is closed at its outer side by the outer ring 35. The inner wall of the groove 43 may be curved while the upper and lower walls of the groove may be flat and join the cylindrical surface 31 of the outer ring 35. The core catcher .body A is provided with spaced slots or openings for carrying the dogs B. Circumferentially spaced vertical slots 39 are provided in the inner ring 36 and vertical openings or slots 46 are provided in the outer ring 35 to join or communicate with the slots 39. The slots 39 extend downwardly from the upper end of the ring 36 and their lower walls form upwardly facing seats or The openings or slots 40 in the outer ring 35 communicate with the lower portions of the slots 39 and their upper ends present downwardly facing shoulders 52.

The dogs B are pivotally mounted in the openings or slots of the body A and are provided to grip and support the core cut by the bit head II. The means for pivotally supporting the core engaging dogs B isa feature of the invention and.

includes pins 42 extending through transverse openings in the dogs 4|. The pins 42 project from the opposite sides of the-dogs B and their projecting end portions extend into! the groove 43 which intersects the slots 391 The projecting end portions of the dog supporting pins 42 are tapered or flattened as at 41 to cooperate with the outer v vertical wall of the groove 43 to positively prevent rotation of the pins. The flattened or tapered portions of the pins 42 at .41, in addition to holding the pins against rotation tend to prevent the pins from shifting longitudinally.

It is an important feature of the invention that the rings 35 and 36 of the body A are securely, detachably connected together in a. manner to positively prevent shifting or displacement of the dog carrying pins 42. The means for connecting the sections or rings 35 and 36 of the body A is simple and permits the easy disconnection of the rings to provide for the repair or replacement of the various parts of the core catcher. The means connecting the body rings 35 and 36 comprises rivets 44 which extend through radial openings in the rings. The rivets 44 intersect or pass through the groove 43 adjacent the ends of the dog carrying pins 42 and thus positively prevent excessive or undesirable longitudinal movement of the pins. The heads or ends of the rivets 44 are preferably flush with the inner and outer surfaces of the body A as illustrated throughout the drawing. It will be apparent how the rivets 44 securely and dependably connect the body rings 35 and 36 and prevent shifting of the pins 42. When it becomes desirable or necessary to disconnect the rings 35 and 36 for the replacement of the dogs B or for other reasons the rivets 44 may be. easily and quickly drilled out to free the rings 35 and 36 for disconnection from one another.

The core gripping and supporting dogs B projectthrough the openings or slots 40 for the purpose to be subsequently described, and are adapted to project into the core passing opening 38 of the body A to engage the core. The upper and lower sides of the dogs B converge outwardly to comparatively sharp edges 46. The dogs B are shaped and proportioned so that they are adapted to be entirely received within the slots 39 with the exception of small parts which may extend into the enlargement 29 of the inner barrel l2. The slots 39 in fully receiving the dogs B allow the dogs to pivot upwardly and outwardly to positions where they are entirely clear of the core passing opening 38 of the body. The opposite vertical sides of the dogs B are preferably fiat to have good bearing engagement with the side walls of the slots 39 when the dogs B are subjected to turning or. twisting forces through their engagement with thecore. v

In accordance with the invention the dogs B are of different lengths whereby certain of the dogs are capable of dependably supporting full sized cores of hard formations while other dogs are adapted to support undersized cores and broken cores. One or more comparatively shortdogs B are provided to grip and retain full sized cores of hard earth formations. The relatively short dogs B have effective angles of attack or engagement with cores of hard earth formations which are usually full sized so that it is practically impossible for a large core or hard core of full diameter to slip through the core catcher when the drill is raised. 'One or more dogs 13 of medium or intermediate length are provided for gripping and supporting cores of soft or relatively soft earth formations which are quite frequently undersized in diameter. The dogs B of medium length are capable of effectively gripping and supporting cores that might not be properly engaged or contacted by the shorter dogs B One or more comparatively long dogs 13 are provided for supporting and catching cores that are badly brokenor shattered. The dogs 13 are adapted to project substantial distances into the opening 33 to prevent pieces or fragments of badly broken cores from passing through the core catcher as the drill is raised. In accordance with the broader aspects of the invention there may be any desired or practical number of dogs B provided on the. body A. In the, particular case illustrated in the drawing there are two diametrically opposite dogs B two diametrically opposite dogs B and two diametrically opposite dogs B The means C for operating the dogsB into en-. gagement with the core normally yieldingly urges the dogs against the core and acts to positively pivot the dogs into the core upon upward movement of the drill. The dog actuating means C includes springs 49 for yieldingly urging the dogs against the coreand cam parts 54 on the dogs for cooperating with a part or shoulder on the core drill to positively actuate the dogs into the core when the drill is raised. Anotch 48 is provided in the outer or pivoted end portion of each dog B to carry a spring 49. The notches 48 intersect the openings passing the pins 42 and the springs 49 surround the pins where they pass through the notches. The springs 49 are helical torsional springs and each spring has an end bearing against a body shoulder 31 and an end bearing against the inner wall of a notch 48. The springs 49 are under torsional strains to normally urge the core engaging dogs B downwardly and outwardly into the body opening 38'. The spring carrying-notches 48 are spaced between the opposite vertical sides of the dogs Bso that both sides of each dog present an extensive surface for bearingagainst a side wall of a slot 39. The springs 49 in urging the dogs B downwardly and inwardly into the opening 38 yieldingly hold the dogs in contact with the core during the drilling operationto resist turning of the core catcher.

The body A in being rotatably' supported in the drill as described above, has little tendency to rotate with the drill so that the spring urged engagement of the dogs B with the core may hold the core catcher against'turning without subjecting the dogs or other parts' to excessive wear or strains.

The body A is arranged for limited longitudinal movement in the core drill and the cam parts 54 are provided to cooperate with a part of the drill to forcibly actuate the dogs B againstor into the core when the drill is raised or moved upwardly relative to the body A. The cam parts 54 are provided on the outer portions of the dogs B which extend into the openings or slots 40. The cam projections or parts 54 protrude through the slots 40 so as to engage the shoulder 2'! in the bit head I I. During the drilling operation the springs 49- yieldingly hold the dogs B in engagement with the. core, thereby resisting downward movement of the core catcher with respect to the core so that'the body vA is held upwardly in the recesses 25 and 33. This spaces the cam-parts 54 above the shoulder 21. After a core of suflicient length has been obtained and the drill is raised to recover the core, the spring urged engagement of the dogs B with the core resists upward movement of the core catcher so that the shoulder 21 is brought into contact with the cam parts 54. The upwardly moving shoulder 21 engaging the cam parts 54 forcibly pivots the dogs B downwardly andinwardly into the opening 38 in the body A to come into effective gripping and supporting engagement with the core. The camming engagement of the cam parts 54 with the shoulder 21 aids the springs 49 in their actuation of the dogs B and insures the positive =inward pivoting of the dogs.

' against rotation.

the dogs B against further downward movement when in the fully actuated positions. Each dog B is provided with a-fiat surface 50' adapted to cooperate with a seat 54 and a fiat surface 53 The adapted to cooperate with a shoulder 52. surfaces 50 and 53 are located so that they come into engagement with the body seats 5! and 52 when the dogs reach their fully extended or operated positions. The stop faces 50 and 53 are located at the opposite sides of the pivotal axes of the dogs and are efiective in positively limiting further downward pivoting of the dogs B when in bearing engagement with the seats 5| and 52. In addition to the support offered the dogs B by the engagement ofv the faces 59 and 53 with the body seats, the cam parts 54 or the protruding parts of the dogs B engage the shoulder 21 of the drill to support the dogs against outward thrusts. The dog supporting pins 42 are thus relieved of severe strains when the dogs B are operated to break the core free from the formation and when the dogs are carrying the core. I

It is believed that the utility and practicability of the core catcher provided by this invention will wardly against the core as the drill is rotated andfed downwardly, and the yielding contact of the dogs with the core may hold the .core catcher the dogs B with the core resists downward movement of the core catcher so that the body A of the core catcher may remain in the upper portion of the recess 25 and the recess 33 during drilling. The slots 39 are such that they are capable of allowing the dogs B to move to their fully out or unactuated positions where they allow the free passage of a large core through the core catcher. The cam parts 54 are spaced vertically out of engagement with the shoulder 21 when the core catcher body A is held in its up position, as described above, so that they have no tendency to force the-dogs B into the core.

When'the drill is raised to actuate the dogs B and to remove the drill and the core from the well, the engagement of the spring urged dogs B with the core tends to hold the body A against actuation of the dogs B to their fully operated The dogs B in being of different positions. lengths are adapted to engage and support undersized and broken cores as well as full sizedcores of hard earth formations. When in sup- Further, the engagement of i porting engagement with the core the dogs B are 4 42 are relieved of severe strains. The opposite vertical ends of the dogs B may engage the vertical walls of the slots 39 when the dogs are sub.-

jected to turning or twisting forces and the pro- I vision of the springs 49 in the notches 43 does not complicate or weaken the pivotal mountings of the dogs. The rivets efiectively connect the rings or sections 35 and 35 of the body A and operate to prevent longitudinal shifting or displacement of the dog carrying pins 42. If it beapplication herein described, but wish it to be' considered as including any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims:

Having described our invention, we claim:

1. A core catcher including a body comprising two rings in telescopic relation, there being an annular groove between the rings and slots in the body intersecting the groove, core engaging dogs extending into the slots, pins pivotally carrying the dogs and having their end portions supported in the groove, and connecting members extending through openings in the rings to connect the rings and intersecting the recess to prevent movement 01' the pins.

2. A core catcher including a body. comprising two rings in telescopic relation, there being an annular groove between the rings and slots in the body intersecting the groove, core engaging dogs extending into the slots, pins pivotally carrying the dogs and having their end portions supported in the groove, the pins having substantially flat parts engaging the wall of the groove to prevent rotation of the pins, and means detachably connecting the rings.

3. A core catcher including a body and a plu-' rality of circumferentially spaced rigid core engaging dogs pivotally carried by the body in a common horizontal plane, the dogs being different lengths. 1

4. A core catcher including a sectional annular body, a plurality of core engaging dogs, independent pins pivotally supporting the dogs, the

pins being removably carried in an opening between sections at the body, and meansdetachably connecting the sections of the body and preventing movement of the pins in the opening.

5. A core catcher including a sectional annular body, a plurality of core engaging dogs, pins pivotally"supporting the dogs, the pins being removably carried by the body, and rivets extendin through openings in the sections of the body adjacent the ends of the pins to connect the sections and to'p'revent movement of the pins.

6. A core catcher including a body having an opening for passing a core and a plurality of circumferentially spaced rigid dogs pivoted on the body in a common horizontal plane for engaging the core, some of the dogs being adapted to project a relatively short distance into the opening to bite into-a core of large. diameter, other dogs being adapted to project a greater distance into the opening to bite into a core oi smaller diameter, the short dogs being spaced between the longer dogs.

7. A core catcher including abody having an opening for passing a core and rigid dogs pivotally carried by the body at circumferentially spaced points in a common plane for engaging the core,

one dog being adapted to project a relatively short distance into the opening to bite into a core of large diameter, another dog being adapted to project a greater distance into the opening to bite into a core of smaller diameter, and a third dog being adapted toproject a still greater distance into the opening to catch a broken core.

8. A core catcher including a body having an opening for passing a core, the body comprising separable sections, there being a groove between contacting parts of the sections, a dog, a removable pin carrying the dog for pivotal movement and supported in the groove, and removable members connecting the sections and intersecting the groove to prevent displacement oi the pin.

JOHN 'H. HOWARD. ALFRED C. CA'I'LAN'D. 

